Vesicle motion is more sensitive to cytoskeletal perturbation on softer substrates. (A) Vesicle dynamics on glass is not strongly affected by cytoskeletal perturbation. However, the effect becomes more pronounced on (B) 40 kPA gels and (C) 10 kPa gels. Relative to the control vesicle motion, MSD plots suggest colchicine treatment decreases motion and cyto-D increases motion. (Number of experiments/cells/trajectories - glass: control 13/31/6738, blebb 8/19/4498, colch 8/16/2111, cytoD 8/18/3984; 40 kPa: control 10/30/3484, blebb 8/16/2412, colch 8/16/1324, cytoD 8/16/2139; 10 kPa: control 10/27/1855, blebb 8/15/773, colch 8/10/532, cytoD 8/12/797; S.E.M. shown as shaded background).